Electric plug



y 1939- N. CHIRELSTEIN 2,159,939

' 1 ELECTRIC" PLUG Filed Aug. 23. 1937 wavy:

EU! l 1 Patented May 23, 1939 UNITED STATES PATENT OFFICE 2,159,939 ELEo'mIorLUG Nathan Chirelstein, Chicago, Ill.

Application August 23, 1931, Serial No. 160,379

3 Claims.

My invention relates to electric plugs.

The object of my invention is to provide an improved blade construction for use in making electric plugs whereby a blade made of thin resilient metal may be formed from a strip thereof to provide a stiff strong blade that will not bend under normal conditions of use.

A further object is to provide such a blade with a branch portion formed integral therewith that is resilient and serves as a spring; the construction being such that the finished blade contains a minimum amount of metal so that its weight will be low, and may be made at a low cost. 9 Referring to the drawing which forms a part of the specification:

Fig. 1V is a vertical sectional view of a portion of a male and a female member of a plug in normal interlocked relation, and a vertical sectional view of one form of blade embodying my invention,

carried by the male member of the plug.

Fig. 2 is a front elevational view of the blade shown in Fig, 1 illustrated on an enlarged scale. Fig. 3 is a side elevational view of the blade shown in Fig. 2.

Fig. 4 is a similar view to that shown-in Fig. 3, with the branch formed straight instead of with a shoulder as shown in Fig. 3.

Fig. 5 is a vertical sectional view of a blade having its branch struck out from the stem of thebody portion between the reinforced side portions formed by thickening the metal or bending it at an angle to the stem to form flanges which extend from near the free or distal end of the blade to the base end thereof, or which may extend over the base-plate as illustrated in Fig. 12.

Fig. 6 is an elevational face view of a blade having a branch extending from the distal or free end of the blade and formed integraltherewith.

and equal in width to the width of the blade at their junction, the branch portion below the fold a short distance therefrom being reduced in width to permit it to lie between the thickened side portions which extend laterally at an angle from the body or stem portion of the blade.

Fig. '7 is a similar view to that shown in Fig. 6,

showing a modified form of construction.

Fig. 8 is a perspective view of a blade construc- 50 tion formed to provide two branch portions, one of which extends from the free endof the blade and is bent back against the-stem at its junction therewith and extends between the raised side portions thereof when compressed, and the other 55 of which is struck out from the stem and extends in the opposite direction from that of the first mentioned branch.

Fig. 9 is an elevational side view of a blade construction formed for use in a plug body such as shown in Fig. 10, in which construction the base- 5 plate portion such as shown in Fig. 2, is not required.

Fig. 10 is a vertical sectional view of abody portion of a plug made of soft vulcanized rubber in which blades such as shown in Fig. 9, are used 10 and are held in place by a cross-bar.

Fig. 11 is a perspective view of a blade the distal end of which is formed by bending the end of the stem portion back upon itself to provide a stiif end having a rounded smooth surface, the 15 downwardly turned end of the stem resting close to the ends of the flanges and its outer surface resting flush with the adjacent surfaces of the flanges.

Fig. 12 is a perspective view illustrating a form 20 in which the flanges are formed to extend over the base-plate and integral therewith to stiffen both the blade and base-plate; the flanges extending unbroken from the blade to the baseplate. 25

The basic feature of improvement of the blade construction consists in forming the sides of the blade with ribs or flanges to double the thickness of the metal at each side of the intermediate portion called the stem, to provide a stiff body that 30 would otherwise flex under pressure due to the normal flexibility of the metal prior to forming the flanges. A standard blade is about one-sixteenth of an inch thick and its width is about onequarter of an inch. 35

In the present construction, brass formed in a thin flexible strip approximately one-thirty-sec- 0nd of an inch thick, is used in making the blade, and its side edges are flanged to provide a thickness of about one-sixteenth of an inch, thus pro- 40 viding a stiff blade from a thin flexible resilient strip of metal.

20- indicates the female portion of a plug and 2l the male portion thereof.

22- indicates blade terminals carried in the body portion 20-, and 23-23 indicates the slots in which said terminals rest in the usual manner. 1

'24- indicates the base-plate of usual construction and 25- a blade embodying my invention.

. Where the base-plate is used in combination with the blade, the metal at 26 is bent at a right angle to the blade and is resilient at this point which permits the blade to bend and adjust itself in entering the socket of the plug II formed in the female member, due to the separation of the ends of the flanges from the baseplate.

21-2|-respectively, indicate the flanges which extend from the base end of the blade to near the free or distal end thereof, and project outwardly from the stem or middle portion of the blade a distance of approximately one-thirtysecond of an inch, thus making the blade about one-sixteenth of an inch thick along each side and forming a channel 2'l'- between them into which the overturned end portion of the stem. 28 rests as shown in Fig. 11; or the same portion of the blade 28- which forms a part of the branch 29, as illustrated in Fig. 8.

The above arrangement provides a smooth end portion for the blade which permits it to enter the slot and engage the terminal contacts in the female member without trouble.

The construction also provides smooth side portions for the blade along the line 3llin the stamping operation and the flanges protect the edges of the branch which is positioned between them.

The branches are of less width than that of the blades and are of the same thickness as that of the stem portion between the flanges, and by reason of their reduced width they flex easily in the act of coupling while retaining their resilience dueto their thinness, and by their spring action they serve to eiiect a perfect connection with the terminal contacts.

The branch may be formed with a bend or shoulder 29' which extends outwardly from the blade a short distance when the free end of the branch is in the socket and held adjacentthe blade, and serves to increase the pressure of the spring against the terminal contact.

The body portion 2lillustrated in Fig. 10-is known to this art and therefore requires no further description.

In the construction shown in Fig. 7 the stem at the distal end of the blade, is folded over and extends downward toward the base-plate in contact with the stem for a greater distance than as shown in Fig. 2, and the side flanges are made correspondingly shorter without reducing the stiffness of the blade.

The construction shown in Fig. 8 shows the free end of the stem 25 to be reduced in width and the branch 29 to extend from the fold 3I- a distance which positions its free end 32- close to the face 33- of the socket member when the body portions are coupled together.

Formed integral with the stem and struck therefrom is another branch 34- which extends outwardly from the stem in an opposite direction to that of the branch 29, and extends from its point of junction with the stem near its free end, downwardly so that the free end of. the branch rests opposite to the free end 32- of the branch Due to the flanged sides of the blade, its stifiness is not greatly reduced by reason of striking the branch 34- from the stem.

The blades are light in weight and are strong and durable.

The construction of the blades above described may be modified as to dimensions and form without departing from the invention disclosed as defined by the claims.

Having thus described my invention I claim as new:

1. A blade for an electric plug comprising a stem of thin normally resilient metal, a flange at each .longitudinal edge of the stem of substantially the length of the blade extending in the same direction and at right angles to the stem and extending beyond the face of the stem a distance substantially equal to the thickness of the stem forming a pocket between said flanges and rendering the blade substantially rigid in the lengthwise direction thereof, the outer end of the resilient stem beyond said flanges-being bent upon itself to provide a branch overlying the flanged side of the stem and of a width to be received in the pocket between said flanges when the blade is received in a socket, and the branch adjacent its connection withthe stem normally lying in said pocket between the side flanges with the remaining portion projecting laterally of the blade.

2. A blade for an electric plug comprising a stem of thin normally resilient metal, a flange at each longitudinal edge of the stem of substantially the same length of the blade extending in the same direction and at right angles to the stem and extending beyond the face of the stem a distance substantially equal to the thickness of the stem forming a pocket between said flanges and rendering the blade substantially rigid in the lengthwise direction thereof, the outer end of the resilient stem beyond said flanges being bent upon itself to provide a branch overlying the flanged side of the stem and of a width to be received in the pocket between said flanges when the blade is received in a socket, and a secondbranch struck-out from the normally resilient stem between the flanged side edges and projecting laterally from the face of the stem in opposition to the flanges.

3. A blade for an electric plug construction comprising a stem of thin normally resilient metal formed with side flanges which extend at an angle thereto a distance equal to the thickness of the stern, said stem being bent back upon itself at its distal end and extending downwardly between the flanges a short distance and then outwardly therefrom and bent near its free end so that it will rest between the flanges at one side of the blade when the blade is resting in the socket of a plug member while a portion of the branch extends outwardly beyond the outwardly extending flanges of the blade and a branch 

